The Sheath Power Cable (Oxygen-Free Copper Conductor, PVC Insulated) 3240 + 1120 mm² is a multi-core cable specially designed for medium and high-voltage power transmission. With the excellent conductivity of oxygen-free copper conductors and the stable protective properties of PVC insulation layers, it demonstrates efficient and safe transmission capabilities in industrial power distribution, building high-voltage systems and other scenarios, becoming a key transmission component in large-scale power projects.​ The conductor is made of oxygen-free copper with a purity of ≥99.95%, manufactured through a multi-strand compact stranding process. Among them, the 20℃ DC resistance of the 3 main cores of 240mm² is ≤0.0779Ω/km, and that of the 1 neutral core of 120mm² is ≤0.158Ω/km, both far lower than the industry standard, which can minimize energy loss during power transmission. The conductivity of oxygen-free copper is as high as 101% IACS (International Annealed Copper Standard), and it has excellent corrosion resistance, so it is not easy to attenuate conductive performance due to oxidation during long-term use. At the same time, the compact stranding process makes the conductor structure compact, and the outer diameter is reduced by more than 15%, which not only saves installation space but also enhances the resistance to mechanical impact. The tensile strength is ≥240MPa, which can withstand the tensile and bending stress during laying.​ The insulation layer is made of high-density PVC (polyvinyl chloride) material. After optimization with a special formula, its temperature resistance level reaches 70℃, and it can operate stably for a long time in the environment of -15℃ to 70℃. Its volume resistivity is ≥10¹³Ω·cm, and the dielectric loss tangent is ≤0.03 (at 20℃), with stable insulation performance, which can effectively isolate the risk of leakage between cores. PVC material also has excellent chemical resistance, which can resist the erosion of acids, alkalis, greases and other substances, and has passed the GB/T 18380.1-2008 flame retardant test. It can self-extinguish when burning in open fire, with a smoke density rating of ≤75, meeting the use requirements of high-safety level places.​ The overall structure of the cable adopts a "3+1" core design. The main cores are responsible for three-phase power transmission, and the neutral core balances the current, adapting to the three-phase four-wire power distribution system. The sheath layer is made of weather-resistant PVC material with a thickness of ≥2.0mm, a tensile strength of ≥12MPa, and an elongation at break of ≥150%, which can resist the erosion of outdoor environments such as ultraviolet rays, wind and rain, and also has certain oil resistance and wear resistance, protecting the internal structure from mechanical damage. The outer diameter of the cable is about 68mm, and the minimum bending radius is 12 times the outer diameter (static), which is convenient for turning and laying in narrow spaces.​ The current-carrying capacity is suitable for high-power transmission needs: the current-carrying capacity of the main core reaches 450A when laid in air and 580A when laid underground, which can meet the power supply needs of scenarios such as large industrial motors and high-rise building main power distribution. In practical applications, it is widely used in high-voltage distribution trunk lines of industrial plants such as steel mills and chemical plants to connect transformers and distribution cabinets; in super high-rise buildings, it is used as the main cable of vertical distribution shafts to transmit power for the entire building; it is also suitable for backup power lines of large data centers to ensure the continuous power supply of key equipment. Its comprehensive performance enables it to maintain stable operation under complex working conditions, providing reliable guarantee for power systems.